1. Field of the Invention
This invention relates generally to acoustic hearing protective devices and, more particularly, to an earplug having a plurality of visual zones which provide a method of indicating the depth of insertion of the earplug and the level of sound attenuation.
2. Brief Discussion of the Prior Art
Environmental sounds are typically comprised of a mixture of various sound wave frequencies having varying intensities. It is well documented that repeated or prolonged exposure to sounds of sufficiently high sound pressure level will cause temporary or permanent hearing loss. For example, exposure to sound waves of some frequencies and of varying intensities under prolonged exposure can damage the auditory organ and cause serious hearing problems, including deafness. Injurious noises such as those caused by explosions or bursts are often comprised of a mixture of sound wave frequencies of varying intensity. These disturbing frequencies are in both the high and low frequency bands and have an intensity sufficient to cause hearing problems. Individuals who are frequently exposed to sound having such disturbing and sometimes dangerous frequencies and intensities run the risk of incurring such injuries as hearing loss or even deafness. These individuals include workers at demolition or construction sites, operators of heavy, noisy equipment and those in active military service. Ear (i.e. hearing) protection is needed to prevent a loss in hearing acuity and the gradual increase in the threshold of hearing resulting from extended exposures to loud noise. Sound attenuation devices are known which specifically address this problem. These include conventional earplugs, earmuffs, and the like which function to reduce the negative effects of exposure to dangerous frequencies by limiting the entry of all sound waves into the auditory organ.
One of the associated disadvantages of earplug use is that people generally do not like to place objects into their ears and wear them for periods of time. Also, because by nature, the earplugs are designed to attenuate noise, some users do not properly insert the earplugs into their ears in an effort to be able to more easily communicate with and hear other individuals surrounding the wearer, e.g., co-workers. In addition, many work environments are such that the use of hearing protection is required under corporate or other policies for safety reasons and in this type of work environment, some individuals only partially insert the earplug device into the their ears. To the casual observer, it would appear that these individuals are in compliance with the existing safety rules when in fact the earplugs are not properly inserted and consequently, the advantages offered by the hearing protective device, i.e., earplugs, are not realized and the wearer is exposed to greater levels of noise and greater risks. Even a trained individual, such as a supervisor or other hearing conservationist, may mistakenly believe that the individual is complying with the existing rules based solely on the visual observance of earplugs in the wearer's ears. Unless, the trained individual closely observes the manner in which the earplugs are inserted into the wearer's ears, it is difficult to judge whether any individual is in full compliance with existing safety rules.
Accordingly, it has been found to be very difficult to enforce the use of hearing protection without having spot checks where the degree of insertion of the earplugs into the wearer's ears is observed. When an individual is subjected to a spot check, the individual must discontinue working and thus productivity is lost due to the spot check. As the number of spot checks and the number of persons subjected to them increases, productivity will continue to decrease resulting in lower profitability and increasing production times. As a result, there is a need for a method and hearing protective device which permits the supervisor or another individual to more easily determine whether the wearer is complying with rules, regulations, and the like by wearing the dual hearing protective device.